阅读说明：本技术 一种环氧树脂用改性固化剂及其制备方法 (Modified curing agent for epoxy resin and preparation method thereof ) 是由 胡天昌 李昊坤 秦宝锋 马震 张永胜 胡丽天 于 2021-08-13 设计创作，主要内容包括：本发明涉及一种环氧树脂用改性固化剂,该改性固化剂是指采用缩水甘油醚类对螺环二胺进行加成反应后制得的液态改性螺环二胺类固化剂；其结构式为：,式中R-(1)为四氧杂螺基团,R-(2)烷基基团。本发明还公开了该改性固化剂的制备方法以及采用该改性固化剂制备的胶粘剂组合物。本发明室温下固化环氧树脂且性能良好,采用其制备的胶粘剂组合物具有较高的粘接强度、良好的韧性及抗冲击性能。(The invention relates to a modified curing agent for epoxy resin, which is a liquid modified spiro diamine curing agent prepared by addition reaction of glycidyl ether on spiro diamine; the structural formula is as follows: in the formula, R 1 Is a tetraoxaspiro radical, R 2 An alkyl group. The invention also discloses a preparation method of the modified curing agent and an adhesive composition prepared by adopting the modified curing agent. The invention can solidify epoxy resin at room temperature with good performance, and the adhesive composition prepared by the invention has higher bonding strength and good performanceToughness and impact resistance.)

1. A modified curing agent for epoxy resin is characterized in that: the modified curing agent is a liquid modified spiro diamine curing agent prepared by addition reaction of glycidyl ether on spiro diamine; the structural formula is as follows:

in the formula, R₁Is a tetraoxaspiro radical, R₂An alkyl group.

2. The modified curing agent for epoxy resin according to claim 1, wherein: the glycidyl ether refers to any one of 1, 4-butanediol glycidyl ether, ethylene glycol diglycidyl ether, glycerol triglycidyl ether and pentaerythritol glycidyl ether.

3. The modified curing agent for epoxy resin according to claim 1, wherein: the spirocyclic diamine refers to 3, 9-di (3-aminopropyl) -2,4,8, 10-tetraoxaspiro [5,5] undecane or 3, 9-di (3-aminopropylidene) -1,5,7, 11-tetraoxaspiro [5,5] undecane.

4. The process for preparing a modified curing agent for epoxy resins according to claim 1, wherein: the method comprises the steps of putting 100 parts of spirocyclic diamine in a container, heating to a reaction temperature of 80-120 ℃, gradually and slowly dripping 10-60 parts of glycidyl ether and 1-5 parts of catalyst under a stirring condition, preserving heat at 80-120 ℃ for 1-5 hours after dripping is finished, and finally removing low molecular weight substances in vacuum to obtain the spirocyclic diamine.

5. The process for preparing a modified curing agent for epoxy resins according to claim 4, wherein: the catalyst is any one of dibutyltin dilaurate, tetramethylammonium hydroxide and tetrabutyl titanate.

6. The adhesive composition prepared by using the modified curing agent for epoxy resin according to claim 1, wherein: the composition comprises a component A and a component B, wherein the weight ratio of the component A to the component B is 100: 45-60 parts by weight of the raw materials are mixed and ground for 10-30 minutes to obtain the product; the component A is prepared by mixing 100 parts of epoxy resin, 5-15 parts of accelerator and 3-30 parts of mixed filler in parts by weight and grinding the mixture for 60-120 minutes by a grinder; the component B is prepared by mixing 30-60 parts of modified curing agent and 5-15 parts of coupling agent and stirring for 60-120 minutes by a dispersion machine.

7. The adhesive composition of claim 6, wherein: the epoxy resin is any one or more of bisphenol A epoxy resin including E51 type, E44 type and E35 type or bisphenol F epoxy resin including F44 type and F51 type.

8. The adhesive composition of claim 6, wherein: the accelerant is any one of tri- (dimethylaminomethyl) phenol, triethylamine, triethanolamine, 2-ethyl-4-methylimidazole and thiourea.

9. The adhesive composition of claim 6, wherein: the mixed filler is at least two of quartz powder, silica powder, alumina powder, glass fiber, lignocellulose, titanium dioxide powder, aluminum powder and fumed silica.

10. The adhesive composition of claim 6, wherein: the coupling agent is any one or more of a silane coupling agent or a titanate coupling agent comprising KH550, KH560, KH570, KH792 and DL 602.

Technical Field

The invention relates to the technical field of low-temperature adhesives, in particular to a modified curing agent for epoxy resin and a preparation method thereof.

Background

With the continuous development of aerospace technology and superconducting technology, the application of the low-temperature adhesive is more and more extensive. On one hand, the research of various aerospace systems represented by rockets, satellites and space vehicles is continuously promoted, and extreme low-temperature equipment and environment are one of the main problems faced by the systems. For example, liquid hydrogen and liquid oxygen are commonly used rocket propellants at present, and the adhesive for bonding the related storage tank materials must meet the use requirement below-253 ℃. Meanwhile, the adhesive for the aircraft structural part also has to keep enough corrosion resistance, fatigue resistance, low shrinkage and good vacuum tightness in an ultralow-temperature environment. On the other hand, in the superconducting magnet in the liquid helium temperature region, bonding structures exist in interlayer insulation, turn-to-turn insulation and ground insulation in a magnet coil. In view of the very limited fixed space in the superconducting coil and the special mechanical properties of the superconducting material, the room temperature curing agent has the advantages of simple operation, no damage to the precision of the device and the like, and the improvement of the compatibility (such as linear expansion coefficient, bonding property and the like) of the ultralow temperature resistant adhesive and the superconducting material is particularly important.

Currently, epoxy adhesives are the best choice for material bonding and sealing at low temperatures. However, epoxy adhesives commonly used in low-temperature environments are highly brittle, are less likely to undergo plastic deformation when subjected to a large external force, and are likely to crack or break. The epoxy resin curing agent used at low temperature mainly comprises aliphatic amine, aromatic amine, organic acid anhydride and other curing agents, but the common curing agent has the problems of higher curing temperature, low bonding strength, poorer toughness, high shrinkage, shorter storage period and the like.

Disclosure of Invention

The invention aims to solve the technical problem of providing a modified curing agent for epoxy resin, which can cure epoxy resin at room temperature and has good performance.

The invention also provides a preparation method of the modified curing agent for the epoxy resin.

In order to solve the problems, the invention provides a modified curing agent for epoxy resin, which is characterized in that: the modified curing agent is a liquid modified spiro diamine curing agent prepared by addition reaction of glycidyl ether on spiro diamine; the structural formula is as follows:

in the formula, R₁Is a tetraoxaspiro radical, R₂An alkyl group.

The glycidyl ether refers to any one of 1, 4-butanediol glycidyl ether, ethylene glycol diglycidyl ether, glycerol triglycidyl ether and pentaerythritol glycidyl ether.

The spirocyclic diamine refers to 3, 9-di (3-aminopropyl) -2,4,8, 10-tetraoxaspiro [5,5] undecane or 3, 9-di (3-aminopropylidene) -1,5,7, 11-tetraoxaspiro [5,5] undecane.

The preparation method of the modified curing agent for epoxy resin is characterized by comprising the following steps: the method comprises the steps of putting 100 parts of spirocyclic diamine in a container, heating to a reaction temperature of 80-120 ℃, gradually and slowly dripping 10-60 parts of glycidyl ether and 1-5 parts of catalyst under a stirring condition, preserving heat at 80-120 ℃ for 1-5 hours after dripping is finished, and finally removing low molecular weight substances in vacuum to obtain the spirocyclic diamine.

The catalyst is any one of dibutyltin dilaurate, tetramethylammonium hydroxide and tetrabutyl titanate.

The adhesive composition prepared by the modified curing agent for epoxy resin is characterized in that: the composition comprises a component A and a component B, wherein the weight ratio of the component A to the component B is 100: 45-60 parts by weight of the raw materials are mixed and ground for 10-30 minutes to obtain the product; the component A is prepared by mixing 100 parts of epoxy resin, 5-15 parts of accelerator and 3-30 parts of mixed filler in parts by weight and grinding the mixture for 60-120 minutes by a grinder; the component B is prepared by mixing 30-60 parts of modified curing agent and 5-15 parts of coupling agent and stirring for 60-120 minutes by a dispersion machine.

The epoxy resin is any one or more of bisphenol A epoxy resin including E51 type, E44 type and E35 type or bisphenol F epoxy resin including F44 type and F51 type.

The accelerant is any one of tri- (dimethylaminomethyl) phenol, triethylamine, triethanolamine, 2-ethyl-4-methylimidazole and thiourea.

The mixed filler is at least two of quartz powder, silica powder, alumina powder, glass fiber, lignocellulose, titanium dioxide powder, aluminum powder and fumed silica.

The coupling agent is any one or more of a silane coupling agent or a titanate coupling agent comprising KH550, KH560, KH570, KH792 and DL 602.

Compared with the prior art, the invention has the following advantages:

1. the modified curing agent is a liquid and low-viscosity modified spiro diamine curing agent prepared by addition reaction of glycidyl ether on spiro diamine, and due to the specific spiro structure of the curing agent, the adhesive has a low shrinkage rate in the curing process, and a long chain with a flexible structure is generated by addition of the glycidyl ether, so that the toughness of the adhesive under the ultralow temperature condition after curing is enhanced.

2. The modified curing agent can cure epoxy resin at room temperature, and meanwhile, the pot life is 2-3 hours (the pot life refers to the time from construction to curing after the component A and the component B are mixed in proportion), so that the construction process difficulty can be effectively reduced, and parts and structural members which are not suitable for high-temperature operation are solved.

3. Tests show that the adhesive composition prepared by the modified curing agent has higher bonding strength, good toughness and impact resistance.

Detailed Description

A modified curing agent for epoxy resin is a liquid modified spiro diamine curing agent prepared by addition reaction of glycidyl ether on spiro diamine; the viscosity of the polyurethane is 650-800 mPas, and the structural formula is as follows:

in the formula, R₁Is a tetraoxaspiro radical, R₂An alkyl group.

Wherein: the glycidyl ether is any of 1, 4-butanediol glycidyl ether, ethylene glycol diglycidyl ether, glycerol triglycidyl ether, and pentaerythritol glycidyl ether.

Spirocyclic diamines are 3, 9-bis (3-aminopropyl) -2,4,8, 10-tetraoxaspiro [5,5] undecane or 3, 9-bis (3-aminopropylidene) -1,5,7, 11-tetraoxaspiro [5,5] undecane.

The preparation method of the modified curing agent for epoxy resin comprises the following steps: the method comprises the steps of putting 100 parts of spirocyclic diamine in a container, heating to a reaction temperature of 80-120 ℃, gradually and slowly dripping 10-60 parts of glycidyl ether and 1-5 parts of catalyst under a stirring condition, preserving heat at 80-120 ℃ for 1-5 hours after dripping is finished, and finally removing low molecular weight substances in vacuum to obtain the spirocyclic diamine.

The catalyst is any one of dibutyltin dilaurate, tetramethylammonium hydroxide and tetrabutyl titanate.

The adhesive composition prepared by the modified curing agent for epoxy resin comprises a component A and a component B, wherein the component A comprises the following components in parts by weight of 100: 45-60 parts by weight of the raw materials are mixed and ground for 10-30 minutes to obtain the polishing slurry. The component A is prepared by mixing 100 parts of epoxy resin, 5-15 parts of accelerator and 3-30 parts of mixed filler in parts by weight and grinding the mixture for 60-120 minutes by a grinder; the component B is prepared by mixing 30-60 parts of modified curing agent and 5-15 parts of coupling agent and stirring for 60-120 minutes by a dispersion machine.

Wherein: the epoxy resin refers to any one or more of bisphenol A type epoxy resins including E51 type, E44 type and E35 type, or bisphenol F type epoxy resins including F44 type and F51 type.

The promoter is any one of tri- (dimethylaminomethyl) phenol, triethylamine, triethanolamine, 2-ethyl-4-methylimidazole and thiourea.

The mixed filler is at least two of quartz powder, silica powder, alumina powder, glass fiber, lignocellulose, titanium dioxide powder, aluminum powder and fumed silica.

The coupling agent is any one or more of a silane coupling agent or a titanate coupling agent comprising KH550, KH560, KH570, KH792 and DL 602.

When in use, the adhesive composition is coated on the surface of an aluminum alloy test piece, defoamed at room temperature, and cured at room temperature for 5-10 days; or injecting the adhesive composition into a mold, defoaming at room temperature, and curing at room temperature for 5-10 days.

Example 1

A modified curing agent for epoxy resin: 100g of 3, 9-bis (3-aminopropyl) -2,4,8, 10-tetraoxaspiro [5,5] undecane is placed in a 500ml three-neck flask, heated to the reaction temperature of 100 ℃, then 40g of 1, 4-butanediol glycidyl ether and 1g of dibutyltin dilaurate are gradually and slowly dripped under the stirring condition, the temperature is kept at 100 ℃ for 1h after the dripping is finished, and finally, low molecular weight substances are removed through vacuum, thus obtaining the compound.

The adhesive composition is prepared by adopting the modified curing agent for epoxy resin: prepared by mixing 100g A components and 50g B components and grinding for 30 minutes.

Wherein:

preparation of component A: adding 100g E51 type epoxy resin into a 1L grinding tank, sequentially adding 5g of tri- (dimethylaminomethyl) phenol, 5g of quartz powder and 5g of alumina powder, and grinding for 60 minutes in a grinding machine to obtain the product.

Preparation of the component B: respectively weighing 50g of modified curing agent and 5g of KH550 coupling agent, and placing the materials into a dispersion machine to stir for 60 minutes to obtain the modified epoxy resin.

When in use, the adhesive composition is coated on the surface of an aluminum alloy test piece, defoamed at room temperature, and cured for 7 days at room temperature; or the composition is injected into a mold, defoamed at room temperature, and cured at room temperature for 7 days.

The resulting adhesive compositions were tested for performance and the results are shown in table 1.

Table 1 main performance index of adhesive composition obtained in example 1

Example 2

A modified curing agent for epoxy resin: 100g of 3, 9-bis (3-aminopropylidene) -1,5,7, 11-tetraoxaspiro [5,5] undecane is placed in a 500ml three-neck flask, heated to the reaction temperature of 110 ℃, then gradually and slowly added with 30g of glycerol triglycidyl ether and 1g of dibutyltin dilaurate dropwise under the stirring condition, and after the dropwise addition is finished, the temperature is kept at 100 ℃ for 1h, and finally, low molecular weight substances are removed in vacuum, thus obtaining the compound.

The adhesive composition is prepared by adopting the modified curing agent for epoxy resin: prepared by mixing 100g A components and 60g B components and grinding for 30 minutes.

Wherein:

preparation of component A: adding 100g E44 type epoxy resin into a 1L grinding tank, sequentially adding 7 g triethanolamine, 10g aluminum powder and 5g fumed silica, and grinding in a grinder for 60 min.

Preparation of the component B: respectively weighing 50g of modified curing agent and 5g of KH560 coupling agent, and placing into a dispersion machine to stir for 60 minutes to obtain the modified epoxy resin.

When in use, the adhesive composition is coated on the surface of an aluminum alloy test piece, defoamed at room temperature, and cured for 8 days at room temperature; or the composition is injected into a mold, defoamed at room temperature, and cured at room temperature for 8 days.

The resulting adhesive compositions were tested for performance and the results are shown in table 2.

Table 2 main performance indicators of the adhesive compositions obtained in example 2

Example 3

A modified curing agent for epoxy resin: placing 100g of 3, 9-bis (3-aminopropyl) -2,4,8, 10-tetraoxaspiro [5,5] undecane into a 500ml three-neck flask, heating to the reaction temperature of 100 ℃, then gradually and slowly dripping 50g of pentaerythritol glycidyl ether and 2g of tetramethylammonium hydroxide under the stirring condition, preserving the temperature at 100 ℃ for 1h after finishing dripping, and finally removing low molecular weight substances through vacuum to obtain the product.

The adhesive composition is prepared by adopting the modified curing agent for epoxy resin: prepared by mixing 100g A components and 60g B components and grinding for 30 minutes.

Wherein:

preparation of component A: adding 100g F44 type epoxy resin into a 1L grinding tank, sequentially adding 5g of thiourea, 10g of lignocellulose and 10g of titanium dioxide powder, and grinding in a grinder for 60 minutes to obtain the final product.

Preparation of the component B: respectively weighing 50g of modified curing agent and 5g of KH560 coupling agent, and placing into a dispersion machine to stir for 60 minutes to obtain the modified epoxy resin.

When in use, the adhesive composition is coated on the surface of an aluminum alloy test piece, defoamed at room temperature, and cured for 10 days at room temperature; or injecting the composition into a mold, defoaming at room temperature, and curing at room temperature for 10 days.

The resulting adhesive compositions were tested for performance and the results are shown in table 3.

Table 3 main performance indicators of the adhesive composition obtained in example 3

Example 4:

a modified curing agent for epoxy resin: 100g of 3, 9-bis (3-aminopropyl) -2,4,8, 10-tetraoxaspiro [5,5] undecane is placed in a 500ml three-neck flask, heated to the reaction temperature of 100 ℃, then 40g of 1, 4-butanediol glycidyl ether and 1g of dibutyltin dilaurate are gradually and slowly dripped under the stirring condition, the temperature is kept at 100 ℃ for 1h after the dripping is finished, and finally, low molecular weight substances are removed through vacuum, thus obtaining the compound.

The adhesive composition is prepared by adopting the modified curing agent for epoxy resin: prepared by mixing 100g A components and 45g B components and grinding for 30 minutes.

Wherein:

preparation of component A: adding 100g E51 type epoxy resin into a 1L grinding tank, sequentially adding 5g of tris- (dimethylaminomethyl) phenol, 3g of fumed silica, 5g of alumina powder, 5g of lignocellulose and 5g of titanium dioxide powder, putting into a grinding machine, and grinding for 60 minutes to obtain the nano-silver particles.

Preparation of the component B: respectively weighing 50g of modified curing agent and 5g of KH560 coupling agent, and placing into a dispersion machine to stir for 60 minutes to obtain the modified epoxy resin.

When in use, the adhesive composition is coated on the surface of an aluminum alloy test piece, defoamed at room temperature, and cured for 10 days at room temperature; or injecting the composition into a mold, defoaming at room temperature, and curing at room temperature for 10 days.

The resulting adhesive compositions were tested for performance and the results are shown in table 4.

Table 4 main performance index of adhesive composition obtained in example 4

Tables 1 to 4 show a method for testing high-low temperature cyclic shear strength: the adhesive is prepared according to the GB/T7124-containing 2008 standard, then the adhesive is bonded and lapped on the aluminum alloy/aluminum alloy sample block, the bonded aluminum alloy/aluminum alloy sample block is cooled for 10min at room temperature after being insulated for 1h at 140 ℃ after being solidified according to the program, then the bonded aluminum alloy/aluminum alloy sample block is placed into liquid helium to be quenched to 269 ℃ below zero and insulated for 1h, the temperature is kept for 10min after being kept still (repeated circulation is carried out for 12 times), and then the shearing strength is measured according to the GB/T7124-containing 2008 standard.